When the cat moves its eyes, prominent monophasic waves appear synchronously in the oculomotor and visual systems. These "ponto- geniculo-occipital" waves are present during both wakefulness (PGOw) and REM sleep (PGOREM). This study has three basic objectives. This first is to determine how the brain regulates and controls PGO waves, normally allowing PGOREM to occur during REM sleep and PGOw to occur only during wakefulness. The second objective is to localize PGO wave activity and the pacemaker for this system at the brain stem level, and to determine the pathway from the pacemaker to the visual system. The third objective is to learn what part PGO waves play in the processing of visual information. The achieve these objectives electrodes will be implanted in the oculomotor and visual systems of the cat and recordings will be obtained from the alert, unrestrained animal. Stimulation and lesions will be used to dissect the anatomical features of the PGO wave system. Finally, single unit recordings will be employed to study the interaction between pacemaker and retinal inputs to the visual cortex.